You don’t mention the lengths of your RG-58, but for UHF almost any length is too much, but lossy cable like RG-58 will always make your SWR appear artificially low because less forward power reaches the antenna than passes through the meter so there’s less power to reflect AND much less reflected power reaches the SWR meter after reflecting from the antenna. So although the losses in RG58 is a problem, it’s not the cause of your SWR reading higher.
Second, although a short or an open can be detected by a multimeter, the effect of RF frequencies is completely different. Yes, detecting a short would be reason to discard a connector or a cable, but resistive losses, the 002 (I assume that’s 2 millions?) that you measured are nothing to worry about.
Without a dummy load and antenna/coax analyzer or nanonva your best option is to simply remove a piece at a time, replacing it with a known good component.